Process for purifying liquid hydrocyanic acid



. cyanic acid appears tot/oil Patented Feb. 6,

R & H CHEMICAL CORPORATION, TION GE CALIFORNIA.

PRUCESS FOR PUI-LIFYING LIQUID 1 No Drawing.

1 '0 all 10/ /0711 may ((2)1(6211 I Be it knownthat I, Monrnrnu J. BROWN, a citizen of the United States, residing at l'ios Angeles, in the county oi Los Angeles and State of California, have invented a new and useful Process for Purifying" Liquid Hydrocyanic Acid, of which the following is a specification.

his invention relates to aprocess of manufacturing liquid hydrocyanie acid and has for its object the removal therefrom of "certain gaseous impurities whereby the prope'rties'of the resulting purified product are improved to a marked degree.

It is Well known that hydrocyanio acid can be produced by the reaction of acids upon'meta-llic c'yanides as Well as by various other reactions; also thatunder thecondi tions prevailing for most of such reactions, hydrocyanic acid is produced as a gas; also that it can. ,be easily liquefied at temperatures below its boiling point.

' Suhstzintially u pure liquid hvdizoclvanic' at about at atmosecid boiis at atmospheric pressule 265 C; 1 It may therefore be used pherio temperatures below that point with a fair degree of is concerned. I have found, however, that safety in so far as true boiling under certain clrcumstwnces liquid hydro violently at temperatures as low as 20 C. Under such circumstances a large portion of the contents of the containing vessel has been known to be forcibly ejected, not only causing, a loss of the liquid in question, but greatly menacing the lives of persons or animals that may be near. I have found that this action is caused by gaseous impurities that have been dissolved in the liquid during the process of manufacture and these gaseous impurities are generally contained in commercial liquid hydi'ocyanio acid, as hereto-fore made. I have found in manufacturing l1q-- uid hydroc-yanic acid thathydrocyan-ic acid, Water vapor, carbon dioxide and some other materials, are driven over from the-generator. These go through a rectifying" operation from which there issues hydrocyanic acid gas, carbon dioxide and Water vapo T less are then. all condensed together. whatever process the liquid is manuii tured, it is customary to condense it at/iow temperatures as for example, 0 C. Ztihese low temperatures are used because oI the ceeding volatility of-the material co11- Application filed August 1.

CAQIFOPLNIA, 2w L 33 ANGELYEEE, =3

2, 1920. Flo. it

llifJK. condensing ten:- peratm'es are used. filo cite an example, it have found carbon dioxide dissolves in L mic acid at 0' C. to the extent of about nine volun s oi lion die/side one volume oi. liquid hydrocvanic acit. it, such gas is dissolved in :he liquid, the latter is raised to a temperature higher (1, it is possible for condition of supersaturation to exist so that if at a higher temperature the condition of supersaturation is disturbed, there may be a heavy evolution of carbon di side so rapid asio givethe appearance of violent hoilinfgx, The great solulriiity of carbon. dioxide in liquid h idrocyanicncid and the possitiiiity of supersaturation of carbon dioxideinrliquid lidroc 'anic acid are the exp anation of.- be great da" er liquid li wlroc vanicacidthat with carbon dioxide that the solubility of can increases with d i creusin z te perature'and 2}1'6 none, or a negligible the t c so evolved. the removal of one, the liquid may be cooled, "h '1. l able. and liquid was before h inc). 1.; (aid h rdr is desired shouh' with mono or m: po i. th heating to "n. point will some n X 1e within ten deer mg shoulc r less of no 1 r int ot the liquid.

Tl; ities p in comli 301d, o

ill

lore, subsequently purified.

tics. llloreover. the elimination of the gaseous impurities by natural means not as complete as when the purification is eonducteil according: to the process oi? my invention. llv gaseous impurities. 1 mean mpurit' luiviue boiling points below the boiling point of liquid l vilroovanie acid.

lily process consists in heating" the c0ntaminatetl material artificially so that the purification may be accomplisherl in a very short time. thus making possible. subsequent refrigeration and. marketing oi the material without delay or the necessity of storage. prefer in practicing this process of purification to heat the contaminated liquid almos to its boiling point and to agitate it at such temperature to accelerate the removal of the gaseous impurities. The liquid. hearted anrl the conteiliecl gaseous impurities are clriven off Without any appreciable distilletion 0;: the liquid occurring. The liquid is flowed into a closed tank having a gas (lischarge pipe and a layer of liquid. is maintuined in the tank and heated. Gaseous impurities and liyclrocyanic acirl vapor will be present in the tank above the liquid, but because of the temperature maintained, the gaseous impurities, such as carbon dioxide, cannot redissolve in the liquid. The liquid, with its contaminating gaseous impurities, is flowed into the tank preferably continuously and the liquid free of gaseous iiupurities is flowed from tne tank n'eterably coutiuuously thereby scpa 'atinu" the liquid from the cvolveil After discharge from the tank. the liquid is cool-ed out of contact with cases which will be dirsolvctl therein. ll i191]. the amount of geseousiinpurities is large, an appreciable amount of hydrocyanic acid vapor escapes from the tank during: the .ehullit-ion which-occurs while the gaseous impurities are being eliminated. For this reason, l prefer to refrigerate the vapors issuing from the liquid, anrl thereby recover the liyclrocyanio 'ec'irl which would otherwise be lost. "1-

ereil hyrlrocyauic acicl is heavily ohai with gaseous impurities and 31'1" conduct thispurification, as a. sop-a 7v oration in o der ton-void mixing the rather impure recovered hyrlrocyauic acicl with the regular run ot product. in the applica tion' of, this process of: purification, (to not limit myself to carbon clioxicle the gaseous impurity nor to any SIRQClllO lllGtllOClS securin agritation, method of heating, rue=!;hocls or subsequent cociirg, nor methods of purifying; the cohclensel vapor recoverecl from the heating vessel.

I claim:

l. The process of purifying liquid hydro cyanic acid. containing gaseous impiuiities,

which comprises heating said liquid to substantially its boiling point and separating the liquid from the evolved gaseous ifnpurities.

2. The process of purifying liquid hydroc anic acid containing gaseous impurities, which comprises heating said liquid to with in 10 (3. ct its boiling point and separating the liquid from the evolved gaseous impurities.

3. The process of purifying; liquid hydrocyenic acid, which consists in heating commercial liquid hydrocyanichacicl to drive off the gaseous impurities without vaporizing any appreciable portion of the liquid hyrlr0- eyanie acid.

4/ The process of purifying liquid hydrocyanic acid, which consists in heating com-.- mercial liquid hydrocyanic. acid to drive off the gaseous impurities Without vaporizing any appreciable portion of the liquid hydrocyanic acid, separating the liquiti from the gases and cooling the liquid. 7

5. The process of purifying liquid hydroc-yanic aoicl containing gaseous impurities which comprises heating said liquid to substantially its boiling: polnt, agitating the heated lir uiil, separating th liquirl from the evolved gaseous impurities we. refrigerating the sepora-tecl liquid.

6. The process of purifying liquid hydrocyanic acid containing gaseous. impurities which comprises heating the liquid within 10 C. of its boiling" point, agitating the heated liquid. seperating'the liquid from the evolved gaseous impurities and refrigerating; the separated liquid.

7. The process of purifying liquid hydrocyanic acid containing gaseous impurities which comprises heating the liquid to sub stantially its boiling point, agitating the heated liquid and separating the liquid from the evolved gaseous impurities;

The process of purifying liquid hydroc vanic acid. containing gaseous impurities whit-i comprises heating the liquid. to with.- in 10 of boiling point, agitating" the heatecl liquid and separating the liquid from the evolved gaseous impurities.

f). The process of purifying liquid hydrocysnic eciil containing gaseous lnpurities which comprises heating the liquid to substantially its boiling point and agitating the heated liquirl. r

M. The process of purifying liquirl hy- (lrooyanio acid containing; gaseous impuriwhich comprises heating-the liquid to within 10 C. 0. its boiling point anrl agitating the heetetl liquid.

In testimony whereof, I have hereurito set my hand at Los Angeles, this 4th rlayof-Au- 

